Contact lens for reshaping the altered corneas of post refractive surgery, previous ortho-K or keratoconus

ABSTRACT

A contact lens is fitted to a cornea of a patient&#39;s eye to gradually alter the patient&#39;s cornea during continued wear to reshape the altered cornea conditions such as the corneas of post refractive surgery, post previous Ortho-K. and keratoconus. The contact lens has a plurality of zones that comprise one optical zone, at least one conformation zone, a connecting zones complex, an alignment zone and a peripheral zone. The one or more conformation zones are utilized to conform the angle of the central optical zone, as well as the alignment zone, to compress on the central and mid-peripheral portion of the altered cornea for redistribute cornea tissue to reduce the residual refractive errors, after refractive surgery, or to smooth out the central cornea surface of the keratoconus for better bare or spectacle vision after contact lens are removed.

RELATED APPLICATION

[0001] The present application is a continuation of a co-pending PatentCooperation Treaty International application, filed on Aug. 6, 2003, tothe United States Receiving Office, with International Application No.PCT/US03/24624, which claims priority from a U.S. application, filed onAug. 7, 2002, with application Ser. No. 10/214,652, now U.S. Pat. No.6,652,095. The entire disclosure of the PCT and US applications areincorporated by this reference as though set forth fully herein.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to contact lenses for reshapingcorneas, and more particularly relates to contact lenses for reshapingaltered corneas which are geometrically abnormal, such aspost-refractive surgical corneas for the enhancement of residual myopia,for eliminating over-treated hyperopia and/or presbyopia, and forreshaping irregular corneas such as advanced or severe Keratoconus torestore usable spectacle vision. More particularly, the inventionrelates to contact lenses that are shaped to provide gradual altering ofthe patient's cornea during continued wear to reshape the cornea toeliminate the residual myopia, hyperopia, presbyopia, or astigmatism ofaltered cornea condition. The lens may also be adapted for enhancementof previously Ortho-K altered corneas for adding on myopia reduction.

[0004] 2. Art Background

[0005] Many people experience difficulties with their vision due to anumber of possible conditions. The most common vision problem is acondition known as myopia or nearsightedness. Myopia is a commoncondition where an eye cannot focus on far-away objects because thecornea of the eye is curved too steeply (i.e., where the radius ofcurvature of the cornea is smaller than normal) to provide adequatefocusing at the retina of the eye.

[0006] Another condition is known as hyperopia or farsightedness. Withhyperopia, the eye cannot focus on both far and near objects because thecurvature of the cornea of the eye is too flat (i.e., where the radiusof curvature of the cornea is larger than normal) to provide adequatefocusing at the retina of the eye. Hyperopia is common among youngchildren. Severe hyperopia will induce lazy eye or amblyopia inchildhood. Mild or moderate hyperopia is tolerable and insidious inyoung ages but will cause reading problems in older age.

[0007] Yet, another common problem is astigmatism, where unequalcurvature of one or more refractive surfaces of the cornea preventslight rays from focusing clearly at one point on the retina, resultingin blurred vision. Presbyopia is the most common vision problem inadults 40 years and older. It does not matter whether they areemmetropic (normal condition), myopic or hyperopic in far vision, themiddle-aged population, i.e. over 40 years old, will begin to experiencedifficulty in focusing on close objects, due to the loss of flexibilityof the eye's crystalline lens. Presbyopia may occur and complicate otherrefractive problems such as hyperopia, myopia or astigmatism.

[0008] A normal cornea is usually parabolic in shape, which is steepest(shorter radius) in curvature at, or nearly at, the central portion ofthe cornea and becomes progressively flatter (longer radius) incurvature to the limbus by certain positive e-value, or so-called“positive shape factor. An altered cornea is a cornea that is fardifferent from the normal parabolic shape, having an abruptly protrudedportion or a “negative shape factor” of a human cornea, which may occurnaturally, or results from some refractive surgical procedures.

[0009] The former condition, i.e. “naturally altered,” is bestdemonstrated by Keratoconus, which is manifested by an abruptlyprotruded cone that is usually located slightly inferior (i e. lowerportion of) to the cornea. It would be difficult to obtain useful visionin advanced or severe Keratoconus by spectacles or any type of contactlenses. The final choice to restore useful vision will be corneatransplantation traditionally. However, complications accompanyingcornea transplantation are very common such as irregular astigmatism,graft rejection, infection or recurrence of Keratoconus. That's thereason why any non-surgical method that may rehabilitate Keratoconus andavoid cornea transplantation will be quite valuable.

[0010] The latter condition, i.e. due to surgical procedures, is bestillustrated by the myopic refractive surgery such as LASIK, PRK and RK.The post-operative cornea is usually manifested by an ablated, flattenedcurvature at the center portion of the cornea. It is not uncommon tostill have unsatisfactory vision, even after the refractive surgery,such as residual myopia, over-corrective hyperopia, iatrogenicKeratoconus or irregular astigmatism. The usual ways to manage thepost-operative complications are enhancement operations, wearingglasses, fitting contact lenses or cornea transplantation for the severecases.

[0011] Another conventional approach to treating some or all of theserefractive errors is to alter the corneal shape by wearing contactlenses which are designed to continually exert pressure on selectedlocations of the cornea to gradually force or mold the cornea into thedesired corneal curvature. A retainer lens is then worn on a part-timebasis to prevent the cornea from returning to its previously deformedshape. This method of treatment is commonly referred to asorthokeratology (referred to hereinafter as “Ortho-K”). While Ortho-K istraditionally applied to the normal corneas to correct myopia,astigmatism and hyperopia, its application to the altered corneas hasbeen unexplored, since it is considered very difficult to figure out aproper lens for reshaping the altered corneas. The cornea curvatures ofthese altered corneas are quite irregular, not measurable, or flattenedartificially at the central portion of the cornea. It would be difficultto measure or to apply the conventional cornea information, such ascornea curvatures or eccentricity value of the altered cornea, forpreliminary cornea reconstruction to custom make the Ortho-K lenses.

[0012] For example, conventional Ortho-K contact lenses with a longercentral radius of curvature than the central radius of the cornea areknown to change the shape of the cornea by compressing the surface atits apex. This reshaped cornea has a lengthened radius of curvature inits central zone, which serves to improve myopia. However, on an alteredcornea of post refractive surgery, it would be very difficult to figureout a lens that can compress the dimpled central portion of the alteredcornea for increasing or furthering myopia reduction. It is especiallytrue if the original cornea has already been ablated a lot to correcthigh myopia as that of higher than −8 or −10 diopters. The higher theoriginal myopia the more cornea tissue will be removed during therefractive surgery, and hence more likely to have post-operative visionproblems.

[0013] Ortho-K has been performed in one form or another since the early1970s. Almost all the lenses are designed to mold normal, regularcorneas that are parabolic in shape. Modern Ortho-K lenses are usuallydesigned to precisely match the cornea surface by obtaining informationfrom cornea measurement. The measured information, such as corneacurvatures and eccentricity value, is then put into mathematicalcalculation, known as “preliminary cornea reconstruction,” which in turnforms the basis for figuring out lens specifications for manufacturing.It was thought very difficult to figure out the precise lensspecifications for molding the altered corneas that are flattest atcenter portion of the cornea (post-refractive surgery), or abruptlyprotruded cornea (Keratoconus). Some practitioners have applied theconventional Ortho-K lenses, “trial-and-error,” method (piece-by-piece)trying to mold the altered corneas, but are rarely successful. It wouldbe worthwhile to provide a non-surgical method to mold the alteredcorneas by Ortho-K, which will save the requirement of enhancementoperation or corneal transplantation.

[0014] The upper limit of Orthokeratology has been thought to be −6.00diopters. Although it is possible to reduce myopia up to −10.00 dioptersby the lens design disclosed in my U.S. Patent, No.: 6,543,897, it isstill useful to figure out a contact lens that will further mold thealtered cornea by previous Ortho-K to achieve further Ortho-K reductionin excessive high myopia. The difficulty of furthering reduction on thealtered cornea of previous Ortho-K is quite similar to that of enhancingthe altered cornea of post refractive surgery for adding on myopiareduction.

[0015] U.S. Pat. No. 5,963,297 to Reim and U.S. Pat. No. 5,349,395, No.4,952,045, No. 5,191,365, No. 6,010,219 to Stoyan disclose Ortho-k lensdesigns for myopia reduction. There has been no disclosure of lensesspecifically designed for reshaping the altered corneas. Notwithstandingthe improvements provided by modern Orthokeratology for myopia, thereremains a need for a contact lens that can be used for effective Ortho-Ktreatment of altered corneas to restore useful vision by a non-surgicalway, thus avoiding the enhance operation or cornea transplantation.

SUMMARY OF THE INVENTION

[0016] It is an object of the present invention to provide an Ortho-Kcontact lens that provides effective molding to the geometricallyspecific corneas for improving or restoring vision.

[0017] It is another object of the present invention to provide anOrtho-K contact lens that provides molding to the centrally protrudedcorneas such as those due to Keratoconus.

[0018] It is yet another object of the present invention to provide anOrtho-K contact lens that provides molding to the centrally dimpledcorneas such as those due to post refractive surgical ablation.

[0019] It is yet another object of the present invention to provide anOrtho-K contact lens that provides further molding to the centrallyflattened corneas such as those due to post myopia Ortho-K to achievefurther myopia reduction.

[0020] It is yet another object of the present invention to provide anOrtho-K contact lens that provides further molding to the centrallysteepened corneas such as those due to post hyperopia Ortho-K to achievefurther hyperopia reduction.

[0021] The objects of the present invention are achieved by providing anapparatus and method for molding the altered corneas in a patient's eye.In accordance with a method of the present invention, a contact lens isfitted to a cornea of a patient's eye, the contact lens comprising anOptical zone, an Conformation zone, a connecting zones complex, anAlignment zone and the Peripheral zone. The Conformation zone iscarefully created to conform to the specific geometry of the alteredcornea for correcting the mathematical bias caused by abruptlyprotruded, or dimpled, portion of the cornea. The Conformation zone maybe steeper, or flatter, than the optical zone and works together withthe optical zone to mold the central portion of the cornea, which willsmooth out the protruded cone of Keratoconus, or correct residualrefractive errors of astigmatism, hyperopia or myopia postoperatively.The concept of “adjusting the vaulting,” or “adjusting the bearing,”relationship of the contact lens by a Conformation zone, withoutaltering the original curvatures of the bearing surfaces, to exertconsistent and effective force for cornea molding” is a novel concept,which offers a precisely curved lens for molding the altered cornea, andwhich is different from just selecting trial lenses empirically bytrial-and-error. This novel concept is hereby termed as “conformedmolding” for reshaping the geometrically protruded or ablated alteredcorneas.

[0022] In accordance with one embodiment of the present invention, acontact lens is provided, which comprises a base curve portion of thelens, an Conformation curve portion of the lens circumscribing andcoupled to the base curve portion, a Connecting curves complex portionof the lens circumscribing and coupled to the Conformation curvesportion, and an Alignment curve portion of the lens circumscribing andcoupled to the Connecting curves complex portion, and a Peripheral curveportion of the lens circumscribing and coupled to the Alignment curveportion.

[0023] The goal of this type of lenses is to mold the altered cornea tosmooth out the irregular cone surface of Keratoconus, to flatten thealready-flattened central portion of the cornea for further myopiareduction, or to steepen the already flattened central portion of thecornea for counteracting the iatrogenic hyperopia. This type of lensescan also be applied for continuation of the previous Ortho-K treatmentof excessive myopia to achieve an add-on myopia reduction, based uponthe already-flattened central portion of the altered cornea by Ortho-K.This type of lenses can also be applied for continuation of the previousOrtho-K treatment of excessive hyperopia to achieve an add-on hyperopiareduction, based upon the already-steepened central portion of thealtered cornea by Ortho-K.

[0024] For treating the altered cornea, the original, or hypothetical,cornea of parabolic curvature is determined by the pre-operative record,or by a carefully calibrated standard trial contact lens set, of whichthe lens depth is well known. The hypothetical cornea with parabolicsurface could be looked upon as having a same volume with the alteredcornea covered under the lens. The only difference of the volumesbetween the hypothetical and the altered corneas is the “tear pool”,which means the central dimple of the altered cornea as that of postrefractive surgical or post Ortho-K corneas, or the tear poolsurrounding the protruded cone of Keratoconus.

[0025] The volume of the altered cornea is estimated based on that ofthe hypothetical cornea and its tear pool. The lens, thus designed, canthen be used to conform the altered cornea by transforming thedifference of tear pool into the curvature of the Conformation zone. TheConformation zone can then be looked upon as part of the optical zone,and actually it could be a continuous spherical or aspheric curvecoupled with positive or negative “e value”, according to the type andamount of the tear pool to be conformed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a side schematic outline view of an ortho-k contact lens10 a according to the present invention for use with an altered corneaof post refractive surgery of a patient's eye. FIG. 1a shows astandardized trial contact lens 10 h used for estimating the alteredcornea.

[0027]FIG. 2 is a side schematic outline view of an ortho-k contact lens10 b according to the present invention for use with an altered corneaof Keratoconus of a patient's eye. FIG. 2a shows a standardized trialcontact lens 10 h used for estimating the altered cornea.

[0028]FIG. 3 is a side view of the ortho-k contact lens according to oneembodiment of the present invention for molding of the altered cornea ofpost refractive surgery, of previous myopia Ortho-K, or of Keratoconus,with a base curve being flatter than the central curvature of thehypothetical cornea.

[0029]FIG. 4 is a front view of the ortho-k contact lens of FIG. 3.

[0030]FIG. 5 is a side view of the ortho-k contact lens according toanother embodiment of the present invention for molding the alteredcornea of Keratoconus, or of previous hyperopia Ortho-K, with a basecurve being steeper than the central curvature of the hypotheticalcornea.

[0031]FIG. 6 is a front view of the ortho-k contact lens of FIG. 5

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The following detailed description is of the best presentlycontemplated modes of carrying out the invention. This description isnot to be taken in a limiting sense, but is made merely for the purposeof illustrating general principles of embodiments of the invention. Thescope of the invention is best defined by the appended claims.Additionally, reference have made to my previous U.S. Pat. Nos.6,361,169, 6,543,897, and 6,652,095, which are incorporated by referenceas if fully set forth herein.

[0033]FIGS. 1, 3, 4 illustrate an ortho-k contact lens 10 a according toone embodiment of the present invention. As shown in FIGS. 1 and 1a, thecontact lens 10 a is a centrally conformed contact lens that is adaptedto be worn over the altered cornea 12 a, which is estimated by thestandardized trial contact lens 10 h to have a hypothetical cornea 12 hof a patient's eye 14. The contact lens 10 a preferably has sixcorrection zones, listed from the center of the lens 10 a to the outerperiphery: an optical zone 20 a, a conformation zone 202 a, a connectingzones complex 22 a-24 a, an alignment zone 26 a, and a peripheral zone28 a.

[0034] Optical Zone 20

[0035] Referring to FIGS. 3-6, the optical zone 20(a, b) has a curvaturethat is defined by the base curve 30(a, b). The optical zone 20(a, b) isresponsible for the corrective steepening of the central portion of thealtered cornea 12 a of post refractive surgery, and for flattening (orsmoothing out) of the central portion of the altered cornea 12 b ofKeratoconus, during treatment. The radius of curvature of the base curve30(a, b) can be steeper (i.e. shorter radius) than a measured curvatureof a central portion of the altered cornea 12 a for relieving overtreated hyperopia, or can be flatter (i.e. longer radius) than ameasured curvature of a central portion of the altered cornea 12 a toeliminate residual myopia. It may also be just any arbitrary curvaturethat is equal to or steeper (shorter radius) than the central curvatureof the hypothetical cornea 12 h, but is flatter (longer radius) than thecentral curvature of the altered cornea 12 b for smoothing out theirregular cornea surface in Keratoconus of the altered cornea 12 b.However, the radius may also be flatter than the hypothetical cornea 12h to eliminate the axial myopia of the altered cornea 12 b ofKeratoconus at the same time.

[0036] The lens optical zone 20 a (LOZ) is preferably created equal to,or slightly smaller than, the cornea optical zone (KOZ) of the alteredcornea 12 a of post refractive surgery. The purpose of creating asmaller LOZ herein, is to fit it into the surgically ablated KOZ formolding. On the other hand, the optical zone 20 b is preferably createdequal to or larger than the diameter of the protruded cone in thealtered cornea 12 b of Keratoconus, but sometimes an optical zone 20 bsmaller than the cone is acceptable for the very extensive globus coneof the cornea 12 b. The purpose of a larger optical zone 20 b is toaccommodate the cone underneath the optical zone for molding.

[0037] The definition of the central curvature of the hypotheticalcornea 12 h is a novel concept, in comparison to conventional teaching.Lens designers usually relied on the cornea curvature measurable by thekeratometric devices as the information for designing lenses. That's thereason why the altered cornea 12 a, and 12 b were seldom thoughtmoldable by Ortho-K and remained unexplored. The cornea tissue volumeand the tear pool underneath the dome of a properly selected trialcontact lens 10 h can be looked upon as an integral whole to figure outthe central curvature of the hypothetical cornea 12 h. Three factors,namely, the tear volume of the tear pool, the tissue volume of thealtered cornea 12 a or 12 b underneath the trial contact lens 10 h, andthe volume of the hypothetical cornea 12 h, are mathematicallyinterrelated in terms of sagittal depth, which can be used for figuringout the contact lens 10 a, or 10 b to mold the altered corneas 12 a or12 b, respectively. I will discuss about the relationship later on. Thishypothesis firms up the basis for reconstructing the altered cornea 12a, or 12 b to quite a reliable reference point and obtain the corneacurvatures before cornea alteration, which is called hereinafter “thehypothetical cornea” 12 h. The standardized contact lens used forestimating the hypothetical cornea 12 h is called hereinafter “the trialcontact lens” 10 h.

[0038] A series of standardized trial contact lens 10 h that arecarefully calibrated according to the lens sagittal depth (LSD) andsorted by the reference system, as disclosed in my previous U.S. Pat.No. 6,361,169, can be used as a trial set to probe the altered cornea12(a, b). From that, we can determine the curvatures of the central, aswell as the peripheral, portions of the hypothetical cornea 12 h. Theset is created according to the shapes of common human eyes so thattracing back to determine the curvatures of the hypothetical cornea 12 hwill be quite easy and reliable. The procedure would be much easier ifthe cornea information before cornea alteration is available forselecting a proper trial contact lens 10 h. The central dimple inaltered cornea 12 a (or the surrounding tear pool in altered cornea 12b), plus the volume of the altered cornea 12 a (or 12 b), can be lookedupon as an integral whole, which can then be verified and adjusted asusual to observe the fluorescent patterns of conventional Ortho-K. Somecontact lens practitioners may be experienced in selecting conventionalRGP for an altered cornea by verifying fluorescent patterns, such as“three point touch method” for fitting Keratoconus. The goal of thisinvention is to reshape the altered cornea 12 a, or 12 b by the contactlens 10 a, or 10 b, respectively, to improve the bare vision orspectacle vision temporarily after removal of the contact lenses 10 a,or 10 b. This is quite different from the purpose of conventionalcontact lenses, which are useful only when the contact lenses are wornon the altered cornea. The procedure of trial-fit by the standardizedtrial contact lens 10 h is only a preliminary procedure to estimate thecurvatures of the hypothetical cornea 12 h for figuring out thespecifications for manufacturing contact lens 10 a or 10 b.

[0039] Referring to FIGS. 1, 3 and 4, the curvature of Optical zone 20a, which is the base curve 30 a, for molding the post refractivesurgical altered corneas 12 a can be determined as usual for molding anormal cornea by apical Keratometric readings and targeted powerdisclosed in previous wisdom. The apical Keratometric readings hereinare measured central curvatures from the altered cornea 12 a by anyreliable keratometric devices as the usual way for fitting conventionalOrtho-K, but are usually preferably obtained from topography. Thetargeted power would be the amount of “residual myopia” or “over treatedhyperopia” in conjunction with some over treated power to ensuremolding. The base curve 30 a can be flatter (longer radius), equal to orsteeper (shorter radius) than the central portion of the altered cornea12 a for achieving different purposes. The base curve 30 a will beflatter than the curvature of the central portion of the altered cornea12 a if the purpose is to mold a residual myopia. In contrary, the basecurve 30 a will be steeper than the curvature of the central portion ofthe altered cornea 12 a if the purpose of the contact lens 10 a is tomold an over treated hyperopia.

[0040] The conventional method of fitting a specific RGP contact lensfor Keratoconus is to create a very steep optical zone to vault the coneapex as a cap, followed by a relatively much flatter peripheralcurvature to fit the altered shape of the cornea 12 b instead of moldingit. The method in accordance with the present invention molds theprotruded cones back to the original curvatures, or into an ablationlike cornea with a flatter central curvature to correct “axial myopia”simultaneously, or into a less protruded regular surface for improvingthe spectacle vision.

[0041] Referring to FIGS. 1, 3, 4, and 2, 5, 6, the curvature of opticalzone 20(a, b), which has the base curve 30(a, b), for reshaping thealtered cornea 12 b of Keratoconus can be determined in two differentways. The first one, for milder Keratoconus with the off-centered cone,is to set up the base curve 30 a of the contact lens 10 a flatter thanthe central curvature of the hypothetical cornea 12 h for targeting azero power (known as “emmetropia”) after treatment, which should be ableto mold the protruded cone back to the original curvatures of thehypothetical cornea 12 h, or even turning the protruded altered cornea12 b into an ablation like altered cornea 12 a. The altered cornea 12 bafter molding will become the flattest at the central portion of thecornea, and all the axial myopia could be eliminated simultaneously torestore a relatively good bare vision after removal of the contact lens10 a. However, the base curve 30 a cannot be determined by the usual wayfor molding normal corneas, since the central curvature of the alteredcornea 12 b is usually irregular or not measurable, hence unreliable tobe used for lens design. Instead, the base curve 30 a of the contactlens 10 a can be easily determined mathematically by the base curve ofthe trial contact lens 10 h and the over refracted power by the wellknown rule of tear lens effect in fitting conventional RGP.

[0042] The second method, for the advanced and severe Keratoconus, is todetermine a base curve 30 b of the contact lens 10 b, arbitrarily with acurvature that is equal to or slightly steeper than the centralcurvature of the hypothetical cornea 12 h aforementioned. The mostcommon way is to determine the base curve 30 b to be the mean value ofthe central curvature of the altered cornea 12 b and that of thehypothetical cornea 12 h for the first pair. The function of the opticalzone 20 b now is to offer a space that may accommodate the extensivelyprotruded cone in severe Keratoconus and exerts gentle force on contactsurface of the central portion of the altered cornea 12 b to mold itinto a relatively regular surface for better spectacle vision afterremoval of the contact lens 10 b. The optical zone width 20 b should bedesigned equal to or larger than the widest cone width determined bytopography, by which the cone will be securely covered underneath theoptical zone 20 b of contact lens 10 b.

[0043] There could be alternatives to the spherical curvatures ofoptical zone 20(a, b), which could be an aspheric curvature with plus orminus eccentricity value, or divided into several concentric sphericalor aspheric curvatures to merge with the conformation zone 202(a, b)outward.

[0044] In one embodiment of the present invention, the diameter of theoptical zone 20(a, b) ranges from 3 mm to 8 mm, and the radii of thecurvature for the base curve 30(a, b) ranges from 15.0 mm to 5.0 mm.

[0045] Conformation Zone 202(a ,b)

[0046] Referring to FIGS. 3, 4, 5 and 6, the Conformation zone 202(a, b)has a radius of curvature defined by a predefined conformation curve302(a, b), which is carefully calculated to conform the lens opticalzone 20(a, b) of the contact lens 10 a, or 10 b, to bear on the centralportion of altered cornea 12 a, or 12 b, to mold it into a flatter,steeper or a relatively regular surface, respectively. The conformationcurve 302(a, b) of the conformation zone 202(a, b) may be flatter(longer radius), or steeper (shorter radius) than or equal to the basecurve 30(a, b), according to the type of the altered cornea 12 a, or 12b, to be reshaped.

[0047] Molding Post Refractive or Ortho-K Cornea

[0048] Reference is made to FIGS. 3 and 4. In designing the contact lens10 a for molding the post refractive surgical or the post Ortho-Kaltered cornea 12 a, the conformation zone 202 a could be looked upon asa hooking arm of the steeper outer connecting zones complex 22 a-24 a,to bear the optical zone properly on the central portion of the alteredcornea 12 a. Whilst summation of the zone width of the optical zone 20 aand the conformation zone 202 a should be designed nearly equal to orslightly smaller than the surgically ablated or Ortho-K molded opticalzone for the optical zone 20 a of the contact lens 10 a to mold thecentral dimple of the altered cornea 12 a effectively.

[0049] The ablated optical zone can be estimated by measuring the corneatopography. The hypothetical cornea 12 h offers us a reference point forestimating the dimple depth to be conformed, which theoretically equalsto the sagittal depth difference, within the scope of the ablatedoptical zone width, between the central curvature of the hypotheticalcornea 12 h and that of the altered cornea 12 a in reshaping residualmyopia, or the difference between the central curvature of thehypothetical cornea 12 h and that of the contact lens 10 a in reshapingover treated hyperopia. The dimple depth could then be subtracted fromthe sagittal depth of the hypothetical cornea 12 h to figure out thesagittal depth of the contact lens 10 a.

[0050] The conformation curve 302 a of the contact lens 10 a could thenbe figured out, which is usually flatter than the outer connectingcurves 34 a-36 a to form a centrally hooking portion, of which thebending angle is conforming precisely to eliminate the aforementionedtear dimple. Thus, the sagittal depth within the scope of the ablated orOrtho-K molded dimple zone is now successfully transformed into asuitable conformation zone 202 a and its curvature 302 a to form thecentrally hooked portion connected to the outer connecting zones complex22 a-24 a, which allows the optical zone 20 a to bear on the centralportion of the altered cornea 12 a for effective molding. All themathematical terms herein are based upon the well-known method forsagittal depth calculation of a contact lens.

[0051] On the lens 10 a for molding post Ortho-K residual myopia,post-refractive surgical residual myopia, or over-treated hyperopia ofthe altered cornea 12 a, the conformation zone 202 a may preferably beflatter than the outer connecting zones complex 22 a-24 a to hook andbend the optical zone 20 a of the contact lens 10 a so as to cause abearing on the dimple portion of the altered cornea 12 a.

[0052] There could be alternatives to the structures of the conformationzone 202 a and conformation curve 302 a for achieving the “bending” ofthe optical zone 20 a. The conformation zone 202 a may be divided intoseveral adjacent flatter and steeper curvatures, as long as the total“bending angle” is kept the same. It would be of no matter whatinterweaving shape the “hook” may be. The curve may also be substitutedby an aspheric curvature to merge with the optical zone 20 a to form acontinuously and gradually flattening curvature with certain e-value,the “self bending” surface, or to merge with the connecting zonescomplex 22 a-24 a to become part of the zones complex. The main taskherein is to acquire a precisely estimated “bending effect” of theconformation zone 202 a, by the aforementioned principles, to bear thecentral portion of the contact lens 10 a on the dimple portion of thealtered cornea 12 a for proper reshaping.

[0053] Molding Keratoconus Cornea

[0054] Before designing the contact lens 10 b for molding the alteredcornea 12 b of Keratoconus, we have to know the surface map of commonKeratoconus. The protruded cones are usually located inferior to, orbelow, the geometric center of the altered cornea 12 b, forming anabruptly steepened boundary just below the geometric center of thealtered cornea 12 b, above which the cornea surface is usually flattenedforming a highly contrasting interface. The off centered cone of thealtered cornea 12 b of Keratoconus can then be looked upon as the edgeof a semi-ablated cornea surface, in light of the flatter (central andupper) portion of the cornea adjacent to the protruded cone. There mayalso be a dimpled tear pool underneath the optical zone of a properlyselected trial contact lens 10 h. The aforementioned skills used tofigure out the conformation zone 202 a and its curvature 302 a for thealtered cornea 12 a (of post refractive surgery) are all applicable indesigning the contact lens 10 a, for molding the off centered cone ofthe altered cornea 12 b. If properly designed, the contact lens 10 awill expand and smooth out the flatter portion of the cornea adjacent tothe off centered cone and create an effective cornea optical zone forbetter bare vision. However if the protruded cone is located or has beenmolded into a shape located at the central portion of the altered cornea12 b, there would be no conformation zone 202 a or conformationcurvature 302 a needed in designing the contact lens 10 a for molding onthe steeper portion of the central cone, by a very flat optical zone 20a.

[0055] The hypothetical cornea 12 h now offers a reference point forestimating the original sagittal height of the altered cornea 12 b bythe trial contact lens 10 h, and the approximate cornea curvaturesbefore cone protrudes. To achieve the purposes of molding and reshapingthe protruded cone or to smooth out the highly contrasting interface toimprove the correctable vision, by the assigned optical zone 20 a andits curvature 30 a, the contact lens 10 a should be created with aprecisely conformed sagittal height that may exert dual forcessimultaneously on the central portion of the altered cornea 12 b by theoptical zone 20 a, as well as on the mid-peripheral portion of thealtered cornea 12 b by the alignment zone 26 a, for effective corneamolding. The central portion of the altered cornea 12 b will be moldedinto an ablation like smooth surface by the optical zone 20 a of thecontact lens 10 a, with a base curve 30 a that is flatter than thecentral curvature of the hypothetical cornea 12 h.

[0056] The way to figure out the conformation zone 202 a and itscurvature 302 a, for bending the optical zone 20 a beyond the cone tobear on the flatter central and upper portion of the altered cornea 12b, is quite similar to the aforementioned way of hooking and bending theoptical zone 20 a on the altered cornea 12 a. However, since only lowerportion of the cornea is steeper (protruded) instead of a ring shapedsteepening in the altered cornea 12 a, only part of the estimatedbending amount, by and large, about 50%, of it should be conformed. Theouter portion of the lens structure next to the conformation zone 202 ais determined according to the shape of the hypothetical cornea 12 h.The conformation curvature 302 a is usually flatter than the centralbase curve 30 a, where the bending angle is conformed precisely toeliminate the tear dimple aforementioned. The method according to thepresent invention offers a methodology to conform the reverse geometriccontact lens disclosed in my previous US Patent, No. 6,652,095, byfiguring out the conformation zone 202 a and conformation curvature 302a to match the lens for better molding of the altered cornea 12 a.

[0057] In some situations, the contact lens 10 a may be tented up at thelower portion of alignment zone 26 a if the cone is quite extensive andmore peripheral, which may weaken the peripheral compression of the dualforces for effective molding of the altered cornea 12 b. That's thereason why, for the very advanced or even the severe cone, we may haveto assign the base curve 30 b to be equal to or steeper than the centralcurvature of the hypothetical cornea 12 h to match the altered cornea 12b, of which the conformation zone 202 b can be looked upon as anup-stretching arm connected to the adjacent flatter connecting zonescomplex 22 b-24 b, bearing the optical zone 20 b gently on the protrudedportion of the altered cornea 12 b. Any increment in steepness(shortening radius) of the base curve 30 b, by a curvature between theflatter central curvature of the hypothetical cornea 12 h and thesteepest curvature of the cone apex of the altered cornea 12 b, may tentup the optical zone 20 b as well as increasing the tightness of thecontact lens 10 b.

[0058] The sagittal height, which will be increased by the steepenedbase curve 30 b, can be estimated quite precisely according to twofactors, namely the amount of increment in steepness (decrement inradius) of the base curve 30 b from the central curvature of thehypothetical cornea 12 h, and the position of the cone apex off centeredfrom the geometric center of the altered cornea 12 b. The methodology inaccordance with the present invention offers a method to conform thedual geometric (“DG”) contact lens disclosed in my previous patent, U.S.Pat. No. 6,543,897, by figuring out the conformation zone 202 b andconformation curvature 302 b to conform the lens for better molding ofthe altered cornea 12 b.

[0059] To learn the skills of conforming the dual geometric contact lensfor molding the altered cornea 12 b herein is preferably started from acentrally located cone of Keratoconus, or the steepened cornea afterhyperopia Ortho-K, with a base curve 30 b matching to the centralcurvature of the hypothetical cornea 12 h. The hypothetical cornea 12 hcan be looked upon as a neutral point. Thus these three geometriccenters of the hypothetical cornea 12 h (neutral point), that of thealtered cornea 12 b, and that of the contact lens 10 b will be coaxialtheoretically. Any increment in the steepness (decrement of radius) ofthe base curve 30 b, will add sagittal height to the optical zone 20 b,also to the height of the contact lens 10 b, so that the contact lens 10b will be tented up for that amount coaxially. The increased sagittalheight, within the scope of the optical zone 20 b, can be figured outand subtracted from the total lens height of the contact lens 10 b, byfiguring it into the conformation curvature 302 b, which is usuallyflatter than the base curve 30 b, to restore the original bearingrelationship of the optical zone 20 b on the central portion of thealtered cornea 12 b.

[0060] In higher hyperopia situations, the altered cornea 12 b of postprevious hyperopia Ortho-K by dual geometric lenses (as described in myprevious U.S. Pat. No. 6,652,095), may have residual refractive errorsresulted from a centrally flattened area (known as a “central lake”),which is caused by the residual vaulting space underneath the steeperoptical zone of the said dual geometric contact lens. The residualvaulting space underneath the optical zone 20 b of the contact lens 10 bcan be diminished or eliminated by incorporating the aforementionedconformation zone 202 b to restore the contact relationship of opticalzone 20 b to bear on the central portion of the altered cornea 12 b foradd-on hyperopia reduction. The amount to be conformed is usually set tobe about 50% of the initial vaulting underneath the said dual geometriclens (as described in my previous U.S. Pat. No. 6,652,095) for hyperopiamolding, but may also be determined individually according to differentzone widths of the “central lake” on the altered cornea 12 b aftermolding, which can be easily determined by modern topography.

[0061] In most situations, the cones of the Keratoconus are seldomlocated right on the geometric center of the altered cornea 12 b, butare usually decentered inferiorly. The bearing point, on the alteredcornea 12 b, of the contact lens 10 b will be also off centeredinferiorly to the same extent, The way to estimate the conformation zone202 b and conformation curve 302 b would be quite different from thecoaxial cone aforementioned. The off centered cone will form some tearspace underneath the central portion of the contact lens 10 b. Therewill be also raised edge at lower portion of the contact lens 10 baccordingly.

[0062] Any increment in steepness (decrement in radius) of the basecurve 30 b over the central curvature of the hypothetical cornea 12 h,will further tent up the optical zone 20, and increase the tear heightunderneath the central portion of the contact lens 10 b asaforementioned. However for an off centered cone, the increment insteepness of the base curve 30 b will also shift the initially offcentered bearing point on the contact lens 10 b closer to the geometriccenter of the optical zone 20 b, and hence substantially diminish thecentral tear height inversely. The net increment of the tear height dueto the steeper base curve 30 b could then be determined by these twoinversely related factors and figured into the conformation curvature302 b of the contact lens 10 b to offset the increased central tearheight and bear the optical zone 20 b properly on the protruded portionof the altered cornea 12 b for effective reshaping.

[0063] The inverse effect of decrement in central tear height with asteeper base curve 30 b is positively related to the off centeringdistance of the cone. For better understanding, if the cone apex issupposedly located right at the outmost margin of the optical zone ofthe trial contact lens 10 h, the lens center will be significantlytented up due to the totally off centered cone. Any increment in thesteepness of the base curve 30 b of the contact lens 10 b will notreally increase (0% increment) in the central tear height, but should be100% offset innately due to the totally off centered cone until theincrement of the steepness of the base curve 30 b reaches the curvatureof the cone apex. There won't be any conformation zone 202 b or itscurvature 302 b needed to mold the totally off centered cone. In anotherword, the contact lens 10 b for a totally off centered cone will beself-conformable. The optical center of the contact lens 10 b, withincreasing steepness of the base curve 30 b, will reposition itselfslightly off centered moving closer to the cone apex of the alteredcornea 12 b. The initially lifted edge of the contact lens 10 b will bealso less elevated accompanying the self-conformation of the contactlens 10 b. On the other hand, any increment in the steepness of the basecurve 30 b will be 100% reflected in the increment of the central tearheight underneath the contact lens 10 b with a centrally located cone asaforementioned. The conformation zone 202 b and conformation curve 302 bshould then be created to offset the increased central tear height forbearing the optical zone of the contact lens 10 b properly on thealtered cornea 12 b. The inverse effect of diminishing (decrement in)central tear height accompanying a steeper base curve 30 b, in betweenthese two ends of cone positions above mentioned, will be positivelyrelated to the radial distance measured from the geometric center of thealtered cornea 12 b to the outmost portion of the cone by topography.

[0064] Generally speaking, the main purpose of the conformation zone 202b in the contact lens 10 b for managing Keratoconus is to offset thesagittal height that is tented up accompanying the increment (decrementin radius) of the steepness of the optical zone 20 b, to restore thecentral bearing relationship of the optical zone 20 b on the cone apexof the altered cornea 12 b for effective molding by dual forces. Theamount of the sagittal height to be offset can be figured outmathematically according to three variables of:

[0065] 1) The sagittal height of the optical zone 20 b with a base curve30 b steeper than the central curve of the hypothetical cornea 12 h;

[0066] 2) The sagittal height of the hypothetical cornea 12 h within thescope of the optical zone 20 b;

[0067] 3) The off center radial distance of the cone apex from thegeometric center of the altered cornea 12 b;

[0068] The sagittal difference between (1) and (2) should be adjusted byfactor (3) to acquire the sagittal height to be offset by theconformation zone 202 b, which can be transformed into the conformationcurvatures 302 b by well known mathematical rules for sagittal depthcalculation. The factor (3) is usually set to be about 50% of the totalsagittal height to be conformed. The reason is, most of the time thecone usually locates just below the geometric center of the alteredcornea 12 b and the optical zone 20 b is usually set to be equal to oronly slightly larger than the cone width as aforementioned. Thus thecone apex will locate at about half way (50% off center distance) of theoptical zone 20 b. That is to say, by and large, about 50% of thesagittal depth difference between (1) and (2) could be conformedinnately by the 50% off centered cone, and the remaining 50% of theincreased tear depth should be compensated by the conformation zone 202b and the conformation curve 302 b.

[0069] On the other hand, for smaller central cones, the contact lens 10a with a base curve 30 a flatter than the central curvature of thehypothetical cornea 12 h can be used to mold the altered cornea 12 binto another altered cornea 12 a forming an ablation like surface asaforementioned. It is actually possible firstly to use the conformedcontact lens 10 b to mold an off centered advanced or sever cone into asmoother central cone, followed by a consecutive contact lens 10 a withflatter optical zone 20 a to further reshape the altered cornea 10 binto another altered cornea 10 a with an ablation like central curvatureto achieve crisp bare vision.

[0070] If the base curve 30 a is assigned flatter than the centralcurvature of the hypothetical cornea 12 h for smoothing out the highcontrast interface and relieving the axial myopia as well, theconformation zone 202 a and curvature 302 a will be usually assignedflatter than the outer connecting curves 34 a-36 b to hook and bend theoptical zone 20 a over the cone to bear the optical zone 20 a of thecontact lens 10 a on the flatter upper portion of the alter cornea 12 b.On the other hand, if the base curve 30 b is assigned steeper than thecentral curvature of the hypothetical cornea 12 h, the conformationcurvature 302 b will be flatter than the base curve 30 b to form anadaptation arm, of which the angle can be precisely figured out byaforementioned three factors. Thus, with the help of conformation zone202 b and its curvature 302 b, the properly conformed contact lens 10 bwill be able to bear on the protruded cone gently by the optical zone 20b, as well as to compress on the peripheral portion of the alteredcornea 12 b by the alignment zone 26 b simultaneously for effectivemolding. All the mathematical terms herein are based upon the well-knownformula for sagittal depth calculation, but are limited to the scope ofthe optical zone 20 b and the conformation zone 202 b.

[0071] There could be alternatives to the structures of the conformationzone 202 b and conformation curve 302 b for offsetting the vaulting ofthe optical zone 20 b. The conformation zone 202 b can be divided intoseveral successively flatter and steeper curvatures, as long as thetotal “bending or offsetting angle” or “bending or offsetting amount” iskept the same. It would be of no matter what interweaving orintermediate shape the conformation zone 202 b may be. The conformationcurve 302 b may also be flattened to such an extent that it becomes zeroor minus in power (diopters), which is actually a plane surface orconvex in shape defined mathematically. The curve may also besubstituted by an aspheric curvature to merge with the optical zone 20 bto form a continuous and gradually flattening curve with a positivee-value, the “self bending or offsetting” surface, or to merge with theinner connecting zone 22 b to become part of the connecting zonescomplex 22 b-24 b. The only requirement is always keeping a proper“bending or offsetting effect” by the conformation zone 202 b and itscurvature 302 b to allow the optical zone 20 b to compress on thecentral portion, and to allow the alignment zone 26 b to compress on theperipheral portion of the altered cornea 12 b.

[0072] In one embodiment of the present invention, the diameter of theconformation zone 202(a, b) ranges from 0.1 mm to 3.0 mm. The radius ofcurvature for the conformation curve 302(a, b) is 1-60 diopters flatter(longer radius) than the base curve 30 b in a conformed contact lens 10b or 1-60 diopters flatter (longer radius) than the outer connectingcurves 34 a,-36 a in contact lens 10 a for different contact lens 10 aor 10 b.

[0073] Although the present invention illustrates the provision of oneconformation curve 302(a or b), it is also possible to provide thecontact lens 10(a or b) with two or more conformation zones and curves,as well as substitute the zone with an aspheric curve of certaine-value, or even merge with connecting zones complex 22-24(a or b) toform a continuously flatter or steeper curvature connecting to theoptical zone 20(a or b).

[0074] Connecting Zones Complex 22-24(a or b)

[0075] Referring to FIGS. 3-6, the connecting zones complex 22-24(a orb) acts as a transition region, compression surface, or tear circulationzone between the conformation zone(s) 202(a or b) and the alignment zone26(a or b). The connecting zones complex 22 a-24 a for contact lens 10 amay be considered a combination of the Fitting zone and Facilitate zonedisclosed in my aforementioned U.S. Pat. No. 6,543,897, and theconnecting zones complex 22 b-24 b for contact lens 10 b may beconsidered a combination of the Plateau zone and Fitting zone disclosedin the aforementioned U.S. Pat. No. 6,652,095. However, the sagittaldepth of the connecting zones complex 22-24(a or b), in accordance withthe present invention, is determined by the estimated hypotheticalcornea 12 h, so that the Alignment zone 26(a or b) will bear on theperipheral cornea properly before and after molding.

[0076] Alignment Zone 26(a or b)

[0077] Referring to FIGS. 3-6, the alignment zone 26(a or b) is designedto provide and maintain centration of the lens 10(a, b) by having aradius of curvature that is either the same as, or slightly longer thanthe central curvature of the hypothetical cornea 12 h (i.e., to matchthe peripheral cornea). A predefined alignment curve 38(a or b) definesthe curvature of the alignment zone 26(a or b), which is almost the sameas the hypothetical curvature of the portion of the cornea 12 hcircumscribing the central portion of the cornea 12 h.

[0078] The alignment zone 26(a or b) creates a large bearing area 40 ina region corresponding with the portion of the altered cornea 12 a, 12 bwhere a centering force is created that maintains the optical zone 20(aor b) substantially at the apical center of the altered cornea 12 a, 12b. The alignment curve 38(a or b) is determined by the hypotheticalcentral K, which is estimated by the aforementioned trial contact lens10 h.

[0079] The associated alignment curve 38(a or b) creates a bearing zoneover a large surface area of the altered cornea 12 a, 12 b, which ishelpful in aligning the lens 10 a, 10 b at the apex of the alteredcornea 12 a, 12 b. The alignment zone 26(a or b) and its curve 38(a orb) has been disclosed in the aforementioned U.S. Pat. Nos. 6,543,897,and 6,652,095.

[0080] Alternatively, the alignment zone 26(a or b) can be segmentedinto multiple curves and any combination of any shapes or curves, aslong as sufficient bearing area is maintained.

[0081] Peripheral Zone 28(a or b)

[0082] Referring FIGS. 3-6, the peripheral zone 28(a or b) is designedwith a radius of curvature longer than that of the cornea 12 (a or b),yielding a curvature less than the estimated curvature of a portion ofthe hypothetical cornea 12 h circumscribing the central portion of thehypothetical cornea 12 h that corresponds to the alignment zone 26(a orb). The peripheral zone 28(a or b) has its surface contour defined by apredefined peripheral curve 42(a or b) which has a curvature that nearlyparallels the portion of the hypothetical cornea 12 h underneath it, butis flatter than the hypothetical cornea 12 h. The peripheral zone 28(aor b) promotes tear flow under the contact lens 10 a, 10 b by takingadvantage of a tear pumping action created when the individual blinksthe eyelid. This tear flow allows constant lubrication and oxygenationof the lens-cornea interface and results in a more comfortable andwearable lens 10 a, 10 b.

[0083] Additionally, the peripheral zone 28(a or b) is designed tocreate a slight edge lift which allows easy contact lens removal fromthe cornea 12 a, 12 b. The peripheral zone 28(a or b) and its curve 42(aor b) have been disclosed in the aforementioned U.S. Pat. Nos.6,543,897, and 6,652,095.

[0084] The different radii used to define the base curve 30(a or b), theconformation curve 302(a or b), the connecting curves 34(a or b)-36(a orb), the alignment curve 38(a or b) and the peripheral curve 42(a or b)are calculated after careful examination of the patient's eye and theassociated ocular tissue. The corneal curvature must be measured, theproper contact lens power defined, and the anticipated physiologicalresponse to the contact lens 10 a, 10 b must be determined. Anindividual skilled in the examination techniques of the ocular system istypically capable of performing these tasks.

[0085] For example, the contact lens 10 a of the present invention canachieve a reduction of residual myopia up to −2.0 diopters postrefractive surgery of previous myopia −8.00 D, within a short wearingtime of 6-8 hours a day for initial wearing, and 4-8 hours a day tomaintain.

[0086] Test Lens Kits for Determining a Hypothetical Cornea

[0087] In accordance with the present invention, a kit of test lensescan be implemented to help determine a hypothetical cornea for use withpost-LASIK and post-myopia Ortho-K amendments. The kit comprises areference table and a set of trial lenses. The reference table is usedto determine a conformation data by using one or more of the followingfactors:

[0088] a) pre-operative or pre-ortho-K KM readings;

[0089] b) post-operative or post-ortho-K KM readings;

[0090] c) power reduced before and after operation, or before and afterortho-K;

[0091] d) post-operative or post-ortho-K cornea optical zone.

[0092] The set of trial lenses includes conformed lenses based on theconformation data, in predetermined increments, from the referencetable.

[0093] Another kit of test lenses can be implemented to help determine ahypothetical cornea for use with Keratoconus and post-hyperopia Ortho-Kamendments. The kit comprises a reference table and a set of triallenses. The reference table is used to determine a conformation data byusing one or more of the following factors:

[0094] a) KM readings from a set of normal corneas;

[0095] b) KM readings of at least one of cone apex and post-hyperopiaOrtho-K;

[0096] c) either one, or both, of cone widths of Keratoconus orsteepened cornea zone of hyperopia Ortho-K;

[0097] d) magnitude of off-centering of the cone apex.

[0098] The set of trial lenses includes conformed lenses based on theconformation data, in predetermined increments, from the referencetable.

[0099] It should be pointed out that the use of reference tables, at ageneral conceptual level for finding normal contact lenses, is alreadydescribed in my U.S. Pat. No. 6,361,169.

[0100] Although the present invention has been described in connectionwith the preferred embodiments, it will be appreciated by those skilledin the art that modifications can be made and alternatives utilizedwithout departing from the spirit and scope of the present invention.

EXAMPLE

[0101] A contact lens having the following dimensions were provided fora AA1125 patient post refractive laser surgery (LASIK), which had beenenhanced once due to myopia recurrence:

[0102] <Right eye>

[0103] Preoperative KM: unavailable

[0104] Preoperative refraction: unavailable

[0105] Postoperative Sim-K: 39.11 (8.63), 39.63 (8.52)

[0106] Postoperative residual myopia: −1.75 diopters (myopia −1.75diopters)

[0107] Central K of hypothetical cornea: 44.75 D (estimated by trialcontact lens)

[0108] Ablated cornea optical zone: 5 mm

[0109] Estimated dimple height to be conformed: 52 microns

[0110] Optical zone 20: width 5.0 mm, radius of curvature 9.72 mm

[0111] Conformation zone 202: an aspheric curvature merged with opticalzone by adding an eccentricity of 0.80 to the base curve

[0112] Fitting zone 22: width 0.4 mm, radius of curvature 6.28 mm

[0113] Facilitate zone 24: width 0.4 mm, radius of curvature 7.21 mm

[0114] Alignment zone 26: width 1.6 mm, radius of curvature 7.70 mm withan eccentricity of 0.40

[0115] Peripheral zone 28: width 0.4 mm, radius of curvature 11.00 mm

[0116] Lens power: +2.00 with a front eccentricity of +0.42 tocompensate for the ADD effect resulted from the eccentricity on basecurve

[0117] <Left eye>

[0118] Preoperative KM: unavailable

[0119] Preoperative refraction: unavailable

[0120] Postoperative Sim-K: 39.93 (8.45), 40.99 (8.23)

[0121] Postoperative residual myopia: −1.50-0.50 @ 135 (myopia −1.50 andastigmatism 0.50 diopter)

[0122] Central K of hypothetical cornea: 44.75 D (estimated by trialcontact lens)

[0123] Estimated dimple height to be conformed: 42 microns

[0124] Optical zone 20: width 5.0 mm, radius of curvature 9.58 mm

[0125] Conformation zone 202: an aspheric curvature merged with opticalzone by adding an eccentricity of 0.80 to the base curve

[0126] Fitting zone 22: width 0.4 mm, radius of curvature 6.26 mm

[0127] facilitate zone 24: width 0.4 mm, radius of curvature 7.18 mm

[0128] Alignment zone 26: width 1.6 mm, radius of curvature 7.70 mm withan eccentricity of 0.40

[0129] peripheral zone 28: width 0.4 mm, radius of curvature 11.00 mm

[0130] Lens power: +2.00 with a front eccentricity of +0.35 tocompensate for the ADD effect resulted from the eccentricity on basecurve

[0131] The pair of contact lenses was worn by the patient for 2 days, at7-8 hours a day. After this correction period, the patient experienced amyopia reduction to zero power. This is equivalent to a myopia reductionof −1.75D (spherical equivalent) for both eyes. The maintenance period(of nearly zero power) lasted for all awakening hours with a 5-7 hourmaintenance night wearing. The topography of the cornea is well centeredand has a definite flattening of cornea curvature within the ablatedcentral zone to support an efficient reduction in myopia. This case hasbeen followed for six months with no side effects.

What is claimed is:
 1. A contact lens for reshaping an altered corneawhich has been altered from a pre-altered cornea, said altered corneahaving an abruptly protruded portion, said pre-altered cornea having asagittal height at its central area, defining a hypothetical lenssagittal height, comprising: a first zone having a curvature defined bya first curve; a second zone coupled to said first zone and extendingradially therefrom, said second zone having a curvature defined by asecond curve, said second curve being flatter than said first curve,such that said second curve alters said hypothetical lens sagittalheight without altering said first curve.
 2. A contact lens of claim 1,wherein said second zone shortens said lens sagittal height to matchsaid first zone for compressing said altered cornea, without alteringsaid first curve.
 3. A contact lens of claim 1, wherein said secondcurve is formed based on predetermined conformation data for saidaltered cornea.
 4. A contact lens of claim 2, wherein said second curveis formed based on predetermined conformation data for said alteredcornea.
 5. A contact lens for reshaping an altered cornea which has beenaltered from a pre-altered cornea, said altered cornea having anabruptly protruded, comprising: an optical zone having a curvaturedefined by a base curve; a conformation zone coupled to said opticalzone and extending radially therefrom, said conformation zone having acurvature defined by a conformation curve, said conformation curve beingformed flatter than said base curve; a connecting zones complex coupledto said conformation zone and extending radially therefrom, saidconnecting zones complex having at least a first curvature defining afirst curve and a second curvature defining a second curve, said firstcurve being flatter than said base curve, said second curve beingsteeper than said first curve; an alignment zone coupled to saidconnecting zones complex and extending radially therefrom, saidalignment zone having a curvature defined by an alignment curve, saidalignment curve being flatter than said second curve; a peripheral zonecoupled to said alignment zone and extending radially therefrom, saidperipheral zone having a curvature defined by a peripheral curve, saidperipheral zone forming an edge lift to act as tear reservoir.
 6. Acontact lens of claim 5, wherein said base curve is formed steeper thana predetermined central portion of said pre-altered cornea.
 7. A contactlens of claim 5, wherein said conformation curve is formed based onpredetermined conformation data for said altered cornea.
 8. A contactlens of claim 6, wherein said conformation curve is formed based onpredetermined conformation data for said altered cornea.
 9. A contactlens for reshaping an altered cornea which has been altered from apre-altered cornea, said altered cornea having an abruptly protrudedportion, said pre-altered cornea having a sagittal height at its centralarea, defining a hypothetical lens sagittal height, comprising: anoptical-conformation zone having a predetermined e-value to form atleast one aspherical base curve based on conformation data of saidaltered cornea, said e-value being such that it causes the altering ofsaid lens sagittal height without altering the most central portion ofsaid aspherical base curve.
 10. A contact lens of claim 9, furthercomprising: a connecting zones complex coupled to saidoptical-conformation zone and extending radially therefrom, saidconnecting zones complex having at least a first curvature defined by afirst curve and a second curvature defined by a second curve, said firstcurve being flatter than said base curve, said second curve beingsteeper than said first curve; an alignment zone coupled to saidconnecting zones complex and extending radially therefrom, saidalignment zone having a curvature defined by an alignment curve, saidalignment curve being flatter than said second curve; a peripheral zonecoupled to said alignment zone and extending radially therefrom, saidperipheral zone having a curvature defined by a peripheral curve, saidperipheral zone forming an edge lift to act as tear reservoir.
 11. Acontact lens of claim 9, wherein: said e-value is determined such thatsaid optical-conformation zone alters said hypothetical lens sagittalheight without altering the most central portion of said aspherical basecurve.
 12. A contact lens for reshaping an altered cornea which has beenaltered from a pre-altered cornea, said altered cornea having a dimpledcentral portion, comprising: an optical zone having a curvature definedby a base curve; a conformation zone coupled to said optical zone andextending radially therefrom, said conformation zone having a curvaturedefined by a conformation curve; a connecting zones complex coupled tosaid conformation zone and extending radially therefrom, said connectingzones complex having at least a first curvature defining a first curve,said first curve being sleeper than said base curve, said conformationcurve being formed flatter than said first curve, said conformationcurve being formed such said conformation curve alters said hypotheticallens sagittal height without altering said base curve.
 13. A contactlens of claim 12, wherein said conformation curve is formed based onpredetermined conformation data for said altered cornea.
 14. A contactlens of claim 12, wherein: said connecting zones complex furthercomprises a second curvature defined by a second curve, said secondcurve is flatter than said first curve.
 15. contact lens of claim 13,wherein: said connecting zones complex further comprises a secondcurvature defined by a second curve, said second curve is flatter thansaid first curve.
 16. A contact lens of claim 14, further comprising: analignment zone coupled to said connecting zones complex and extendingradially therefrom, said alignment zone having a curvature defined by analignment curve, said alignment curve being flatter than said secondcurve; a peripheral zone coupled to said alignment zone and extendingradially therefrom, said peripheral zone having a curvature defined by aperipheral curve, said peripheral zone forming an edge lift to act astear reservoir.
 17. A contact lens of claim 15, further comprising: analignment zone coupled to said connecting zones complex and extendingradially therefrom, said alignment zone having a curvature defined by analignment curve, said alignment curve being flatter than said secondcurve; a peripheral zone coupled to said alignment zone and extendingradially therefrom, said peripheral zone having a curvature defined by aperipheral curve, said peripheral zone forming an edge lift to act astear reservoir.
 18. A contact lens of claim 12, wherein said base curveis flatter than a predetermined central portion of said pre-alteredcornea.
 19. A contact lens of claim 13, wherein said base curve isflatter than a predetermined central portion of said pre-altered cornea.20. A contact lens of claim 14, wherein said base curve is flatter thana predetermined central portion of said pre-altered cornea.
 21. Acontact lens for reshaping an altered cornea from a pre-altered cornea,said altered cornea having a dimpled central, said pre-altered corneahaving a sagittal height at its central area, defining a hypotheticallens sagittal height, comprising: an optical zone having a curvaturedefined by a base curve; a conformation/first connecting zone having apredetermined e-value to form at least one aspherical conformation/firstconnecting curve based on conformation data for said altered cornea,said e-value being such that it causes the altering of said lenssagittal height without altering the most central portion of saidaspherical base curve.
 22. A contact lens of claim 21, wherein: saide-value alters said hypothetical lens sagittal height without alteringsaid base curve.
 23. A contact lens of claim 21, further comprising: asecond connecting zone coupled to said conformation/first connectingzone and extending radially therefrom, said second connecting zonehaving at least a second curvature defining a second curve.
 24. Acontact lens of claim 22, further comprising: a second connecting zonecoupled to said conformation/first connecting zone and extendingradially therefrom, said second connecting zone having at least a secondcurvature defining a second curve.
 25. A contact lens of claim 23,further comprising: an alignment zone coupled to said second connectingzone and extending radially therefrom, said alignment zone having acurvature defined by an alignment curve, said alignment curve beingflatter than said second curve; a peripheral zone coupled to saidalignment zone and extending radially therefrom, said peripheral zonehaving a curvature defined by a peripheral curve, said peripheral zoneforming an edge lift to act as tear reservoir.
 26. A contact lens ofclaim 24, further comprising: an alignment zone coupled to said secondconnecting zone and extending radially therefrom, said alignment zonehaving a curvature defined by an alignment curve, said alignment curvebeing flatter than said second curve; a peripheral zone coupled to saidalignment zone and extending radially therefrom, said peripheral zonehaving a curvature defined by a peripheral curve, said peripheral zoneforming an edge lift to act as tear reservoir.
 27. A contact lens forreshaping an altered cornea which has been altered from a pre-alteredcornea, said altered cornea having a dimpled central portion, saidpre-altered cornea having a sagittal height at its central area,defining a hypothetical lens sagittal height, comprising: a first zonehaving a curvature defined by a first curve; a second zone coupled tosaid first zone and extending radially therefrom, said second zonehaving a curvature defined by a second curve; a third zone coupled tosaid second zone and extending radially therefrom, said third zonehaving a curvature defined by a third curve, said third curve beingsteeper than said first curve, said second curve being formed flatterthan said third curve, said second curve altering said hypothetical lenssagittal height without altering said first curve.
 28. A contact lens ofclaim 27, wherein said second curve is formed based on predeterminedconformation data for said altered cornea.
 29. A contact lens of claim27, wherein said first zone comprises a plurality of sub-first zones,each sub-first zone having a curvature defined by a curve.
 30. A contactlens of claim 28, wherein said first zone comprises a plurality ofsub-first zones, each sub-first zone having a curvature defined by acurve.
 31. A contact lens of claim 27, wherein said first zone comprisesan inner and outer zones, said inner zone having an inner curvaturedefined by an inner curve, said outer zone having an outer curvaturedefined by an outer curve, said outer curve is flatter than said innercurve.
 32. A contact lens of claim 28, wherein said first zone comprisesan inner and outer zones, said inner zone having an inner curvaturedefined by an inner curve, said outer zone having an outer curvaturedefined by an outer curve, said outer curve is flatter than said innercurve.
 33. A contact lens of claim 27, wherein said first curve isflatter than a predetermined central portion of said pre-altered cornea.34. A contact lens of claim 28, wherein said first curve is flatter thana predetermined central portion of said pre-altered cornea.
 35. A kit oftest lenses for determining a hypothetical cornea for use withpost-LASIK and post myopia Ortho-K amendment, comprising: a referencetable for determining a conformation data by using at least one offollowing data: pre-treatment KM readings; post-treatment KM readings;Power reduced before and after treatment; post-treatment cornea opticalzone; a plurality of trial lenses, comprising conformed lenses based onthe conformation data in predetermined increments from said referencetable.
 36. The kit of claim 35, wherein: said pre-treatment KM readingscomprise pre-operative or pre-ortho-K readings; said post-treatment KMreadings comprise post-operative or post ortho-K readings;post-treatment cornea optical zone comprises post-operative orpost-ortho-K cornea optical zone.
 37. A kit of test lenses fordetermining a hypothetical cornea for use with Keratoconus and posthyperopic Ortho-K amendment, comprising: a reference table fordetermining a conformation data by using at least one of following data:KM readings from a set of normal corneas; KM readings of at least one ofcone apex and post hyperopic Ortho-K; at least one of cone widths ofKeratoconus and steepened cornea zone of hyperopic Ortho-K; magnitude ofoff centering of the cone apex; a plurality of trial lenses, comprisingconformed lenses based on the conformation data in predeterminedincrements from said reference table.